Process of producing fermentable sugars.



UNITED STATES PATENT OFFICE.

FRANCIS 1-]. GALLAGHER, OF NEWTON, MASSACHUSETTS, ASSIGNOR TO STANDARD ALCOHOL COMPANY. OF NEW YORK, N. Y. A CORPORATION OF MAINE.

PROCESS OF PRODUCING FE'RME-NTABLE SUGARS.

Specification ofLetters Patent.

Application filed July 15. 1912.

No Drawing.

To (17/ whom, it may concern:

Be it known that I, FRANCIS E. GALLA- oi-mn, a citizen of the United States, residing at Newton, in the county of Middlesex and State of Massachusetts, have invented certain new and useful. Improvements in Processes of Producing Fermentable Sugars, of which the following is a specification.

This invention is a process of treating ligno-cellulose or other cellulose raw material for the production of 'fermentable sugars.

It is well known that certain constituents of such cellulosic raw materials assawdust, u-'oor l-\vaste, etc., are convertible, in presence of dilute acids or equivalent hydrolyzing agents, into fermentable sugars; and that the proportion of such sugars formed is dependent upon certain factors, among which may be mentioned the character and concentration of the hydrolyzing agent, and the time and temperature of the cooking or digestion. I have demonstrated by numerous experiments that the reaction whereby such fermentable sugars are formed is in fact highly complex in character; and that the fermentable sugars are to be regarded as representing an intermediate stage rather than the final stage of the conversion of ligno-cellulose under the influence of hydrolyzing agents. In cooking the material at high temperatures, as for instance in treating it with dilute acids under high pressure of steam. I have found that in the early stagesof the cook, there are formed relatively large percentages of soluble substances which comprise a low percentage of fermentable sugars but a relatively high percentage of so-called wood-dextrins. These wood-dextrins are not directly fermentable, but are susceptible of conversion by further hydrolysis into dextrose or similar fernientable sugars. In the later stages of the cook, the dextrose (fermentable sugar) is formed from the wood-dextrin faster than the latter is produced from the cellulose or ligno-cellulose. As the cook is further prolonged, the total quantity of fermentable sugar no longci ---increases, and) may even decrease, due presumably to the decomposition of the sugar under the hydrolyzing influence at a rate approximating or even exceeding the rate of its formation. It is found however that after the wood dextrins have been once formed at high Patented Mar. 18, 1913.

Serial No. 709,564.

temperatures, their conversion into dextrose or equivalent fermentable sugars proceeds satisfactorily at comparatively low temperatures, that is to say under a pressure of steam materially lower than that used for the preliminary cooking, or even at or below the atmospheric boiling-point of the solutlon. It is also found that at such lower temperatures there is materially less liability to the destruction of the fermentable sugars which have been previously formed.

In view of the foregoing considerations, I have found it advantageous, from the standpoint of final alcohol yield, to treat the wood in presence of suitable hydrolyzing agents for a short period of time under relatively high pressure and temperature, and thereafter to continue the hydrolysis of the resulting wood-dextrins at a lower temperature, thus taking advantage of the relative rates of formation of wood-dextrins and dextrose, and of the rate of decomposition of dextrose at different temperatures.

A specific example illustrating the advantage of this procedure is as follows:

1. Sawdust was cooked for fifteen minutes, in presence of one per cent. of sulfuric Total solids 23. 1 percent.

reducing sugars 19.3 fermentable sugars 10. 21 Ratio of fermentable solids to total solids l4. 2 Alcohol yield 5.18per cent...

*2. Sawdust was cooked for fifteen minutes under the above conditions, followed by a supplemental digestion for thirty minutes under a steam pressureof 70 pounds. The composition of the extract was Total solids -i 23. 6 percent. reducing sugars. 19.2 fermentable sugars 12.3%

Ratio of fermentable sugars to total solids 52. 3

Alcohol yield 6.18 per cent.

It will be observed that the principal effect of the supplemental or lower temperature. cook has been to increase the percentage U St it the (lift "here'lroro: it me e to conti us the hydrolysis 1 A retsti .verature and in i l T .4. l D}; e coon rim and other to i cted clple .w tee L re re pr Jlon g 7 ways teW may 1 hours or drs ov 1 alcohol.

e its preliniir red, and the entrnct Stiui. itrmentetion end distillation The "esid known as slop, contains bodies not sue ial and further hoiiec v vessel s, to scour y be otherw or eWh. s o

sence of stew-n, w er temper ed may he i rich tor

us from the rurther n.ydrol ,='sis, eitii r admix ure with snwd t or nigh-te1n- For example, the slop may ed to the digester before or d pleinentel or lower-tel" or itinsy be added to thedigested mater ed in closed or open ther l'iydrolytio action; or it added to the material underg ise er" i 1 gester,

attained the ternientehle state may be subjected to heat under conditions to complete their conversion to such state. its shore pointed out the further treatment ct l these materials may talre place in the dior after the charge has left the digester, or after the soluble matters have been extracted by difiusion, or even l ter thes te'ps of fermentation distillation in the lastanentioned case, it has been wot l he we not ing the material in presence of e hydrol ing agent until e considerable propoi thereof has been rendered soluble end there after continuing the digestion at at lower temperature to increase the quantity of tee ,ihle sugars.

process of producing termenteole si gni's troin ligno-cellulose or other celluials, which consists in digest-- ing the materiel bytlirectaction or stezun under pressure and presenceof a suitable hydrolyzing agent until a suitable proportion thereof has been rendered soluble and thereafter continuing the digestion at at lower temperature to increase the quantity of termenteble sugars.

3. A process of producing terrnentehle sugars from ligno-cellulose or other cellulosie raw materials, which consists in digesting the material by direct action ct steam under pressure and in presence or a, suitelole hydrolyzing agentuntil a suitable pro- {portion thereof has been rendered soluble, and thereatter continuing the digestion ot a lower temperature and tor a lon er period to increase the quantity of termentsble sugars.

in testimony whereof ll atiix my signature v in presence of two Witnesses. 1 1 FRANCIS ll. GALLAGJWTER.

l l itnesses ARTHUR l). Lrrrrn, HARRY Morn.

losic l'fLW meter oh, by addressing the Go;

found essentisl to the best results to edd a.

losie raw material, which consists in digest 

